"I'm a Slave 4 U" garnered mixed reception from music critics. Some critics argued it was the singer's most mature sound at the time compared to her previous singles, while other noticed the song's attempt to leave behind Spears' girl next door image and said her vocals were unnatural. "I'm a Slave 4 U" achieved commercial success, peaking inside the top-ten in almost every country that it charted on. However, the song peaked at number 27 on the Billboard Hot 100 and at number 85 in BillboardHot R&B/Hip-Hop Songs, both being the lowest chart positions of the single worldwide.

"I'm a Slave 4 U" was written and produced by both Pharrell Williams and Chad Hugo, also known as The Neptunes, who also collaborated with Spears on another track from Britney, "Boys" (2002).[1] Both recordings were originally intended for American singer Janet Jackson's seventh studio album, All for You (2001), with her recording an unreleased demo version of the latter before handing the track to Spears.[2][3] "I'm a Slave 4 U" was recorded by Andrew Cleman at Master Sound Studios in Virginia Beach, Virginia and by Brian Garten at Right Track Studios in New York City, being later mixed by Serban Ghenea in New York City. Audio engineering was done by Ryan Smith and Tim Roberts.[4][5] After reading the lyrics for the first time, Spears stated it talks "about me just wanting to go out and forget who I am and dance and have a good time. That's kinda where I am now right now. I love working, but at the same time, I love having a good time."[6]

The song was met with mixed reviews by critics. A review from NME magazine stated that "the song is funk the way God intended —hypnotic, insistent, mysterious, suggestive— and if Prince was a nineteen-year-old former Disney Club host and virgin, he'd be proud to create such a record".[8] Another review from and Allmusic[9] agreed that "I'm a Slave 4 U" was a step towards a more mature sound. Bill Lamb from About.com listed at number nine, on her Top 10 Songs, saying: "By the time of this single off her third album, it was obvious Britney Spears was becoming an adult. This song is a radical shift from the "not quite innocent" 16-year-old schoolgirl of Britney's first album. Slinky and sexy have crept into the Britney Spears style".[10]

"I'm a Slave 4 U" received several comparisons to Janet Jackson, with one critic noting "Spears’ main musical and visual influence has not been Madonna but Janet Jackson". "But Jackson’s not the only influence to appear on “Slave:” the Neptunes’ minimal, electronic production and Spears’ breathy, cooing delivery create a track that smacks of Prince." "Spears, on the other hand, became more and more interesting – and enjoyable – as she continued to explore elements of Janet Jackson and Prince throughout her career."[11] Lyndsey Parker of Yahoo! Music wrote "'Slave,' written and produced by the Neptunes and originally intended for OG pop bombshell Janet Jackson, evoked the old-school sexcapades of Prince and his protégés Vanity 6—and in many ways, it was a real artistic leap."[12]

"I'm a Slave 4 U" peaked at number 27 on the Billboard Hot 100 for the issue date of December 1, 2001,[13][14] becoming Spears' first lead single from an album not to crack the U.S. top ten. The track also became a top 30 hit on the Hot 100 Airplay,[15] but just barely made into the Hot 100 Singles Sales peaking at number 73.[16] The low sales points are due mostly because of the song's 12-inch single release instead of a competitive regular CD single. Despite the little sales, "I'm a Slave 4 U" became Spears' first dance hit, reaching number four on the Hot Dance Club Play chart.[14] It is also her first and, so far, only song to appear on the Hot R&B/Hip-Hop Songs chart, peaking at number 85.[14] In Europe "I'm a Slave 4 U" was more successful, becoming a top ten hit in nearly every country that it charted in, including big markets such as Germany and France, where it was certified Silver by the Syndicat National de l'Édition Phonographique for selling over 125,000 copies.[17] The track spent two weeks at number-five on the European Hot 100 Singles chart provided by magazine Music and Media at the time.[18] "I'm a Slave 4 U" peaked at number-four on the official UK Singles Chart[19] and spent a total of 14 weeks within the top 75 and sold over 150,000 copies.[20] In the Pacific, the track was somewhat successful, debuting at number seven on the Australian Singles Chart. Despite spending a very short period on the chart, eight weeks,[21] it was certified Gold by the Australian Recording Industry Association for shipments of over 35,000 units.[22] In New Zealand, "I'm a Slave 4 U" debuted at number 46 on November 4, 2001 and missed the top ten, peaking at number 13 in its third week. The song spent just six weeks on the chart.[23]

In the video, Spears and fifteen dancers employ the same choreography seen in her with Spears looking over a balcony whilst singing with cars down in the distance. Spears is portrayed as a slave to the music who dances all day until she and the other dancers are sweaty and near dehydration, forcing them to search for water, Spears is standing by a mirror at the sink. Two alternative versions of the video clip can be found on the Greatest Hits: My PrerogativeDVD released on November 9, 2004.[27] The music video was nominated in three categories at the 2002 MTV Video Music Awards for Best Female Video, Best Dance Video, and Best Choreography. The video clip for "I'm a Slave 4 U" was noted for its influence from Janet Jackson, with one review saying "Spears’ main musical and visual influence has not been Madonna but Janet Jackson, particularly in her visual element. The Jackson influence can be seen in the video for 'I’m A Slave 4 U', and it continues through 'Me Against the Music,' 'Boys,' and 'My Prerogative,' as well as her live performances in general."[11] The video ranked #1 in the list of the "50 Sexiest Music Videos of All-Time" published by Canadian music channel MuchMusic in 2007.[28] An official remix video used the "Miguel Migs Petalpusher Vocal Mix" was also released. There are another 2 unreleased remix videos using the Thunderpuss Club Mix and the Thunderpuss Dark Mix. Nearly 10 years later in 2011, the video would be compared to her "Till The World Ends" music video. Several references from the "I'm a Slave 4 U" video were made in the video for "Till The World Ends", such as the dancers crowding around her and the sweaty dancers scene.

"I'm a Slave 4 U" was covered by the musical television show Glee in the episode "Britney/Brittany" sung by Heather Morris in her singing debut. In a dream sequence, Morris's character Brittany S. Pierce sings the number, while recreating several iconic looks from Spears's videos: the red catsuit from "Oops!... I Did It Again", the outfit with a snake from Spears's "I'm a Slave 4 U" performance at the VMA's, and the white diamond bodysuit from "Toxic". Morris also performed the song during the live 2011 Glee Tour.